We have an o6 xc90 that we bought brand new. 2.5 Turbo with around 145,000 miles. Great car! About a year ago the check engine light came on, took it to the shop, o2s had it back 4 days light comes back on, another sensor, had it back about a week, light back on, fuel pump/ regulator?,o git back, about 2-3 weeks, light back on, no codes?, They did a complete reboot, has been fine. Almost a year later check engine light is on again! Different shop, o2 says it was lean during a 17° startup. Could find nothing else, reset computer, week later the light is back! Anyone have any suggestions?Getting very frustrated. Car runs great and has never skipped a beat. Thanks

 

start by buying your own OBD2 code reader. The CEL light shouldn't come on without a fault code being stored. Even if the light goes out the codes should still be there. When you say "took it to the shop, o2s" are you saying they replaced the oxygen sensors? It sounds like the different shop read a fault code pointing to a fuel trim issue (ie running lean) which can be caused by an intake air leak, exhaust leak or one of the other sensors (such as the engine coolant temp sensor or the MAP sensor being wonky). Intake air leaks can be hard to find - a good shop will be able to run a smoke test to see where air may be entering the system. Other causes could be an issue with the throttle body or the idle air valve. SInce you didn't mention any wandering or lump idle issues, these are not a prime suspect. Unless you saw something other than a lean mix fault code, I would also not suspect one of the sensors - which is why you should make note of which codes are presented.

 

Yes they did replace o2 sensor last year. New shop said they suspect an intake leak. Thank you for your help.